The present invention relates generally to a negative feedback system, and more particularly to an error compensation scheme for compensating errors occurred in the negative feedback system.
Negative feedback systems are commonly used in engineering systems to maintain a prescribed relationship between a system output and a system input by comparing them and using the difference as a means of control. This type of systems have a stabilizing equilibrium for the system. Even if there is a change of variable within a stable negative feedback system, it will attempt to establish the equilibrium. A conventional negative feedback system is composed of a forward module, feedback module, and summation module. The feedback module and summation module work together define the relationship between the system output and the system input. For example, the feedback module provides a feedback signal back to the summation module which will subtract the feedback signal from the input signal before providing the forward module with an input signal.
However, this conventional system inherently incurs a gain error. This error will be amplified by the forward module before being output from the system. The error can be further amplified if a system has multiple stages of the negative feedback systems, thereby causing an accumulation of errors. In addition, the conventional negative feedback system also provides a non-linear system output since the forward module has a non-linear gain. This also generates a settling time error, due to the finite bandwidth of the forward module.
Desirable in the art of negative feedback system designs are additional designs that provide a linear output with reduced settling errors, without incurring or accumulating errors.